[Xymon] Postfix queue monitor - no graphs

[Shawn Heisey]

I'm setting up this client-side monitor:

https://wiki.xymonton.org/doku.php/monitors:postfix

I ran into a number of issues, and I've fixed all but one of them.  The
graphs aren't working.  I followed all the instructions on that page,
except that the config files I edited did not have "hobbit" in the name
because I'm running 4.3.14 on the server and 4.3.7 on the client.

What troubleshooting steps do I need to follow to figure out if I did
something wrong with the graphing config and what to change?

The major problem I encountered and fixed was permission related.  The
xymon user cannot read postfix queues, and the postfix user cannot write
to the xymon client tmp directory.  I solved this with these changes to
the client system:

In /etc/sudoers.d/xymon:
xymon ALL=(postfix : xymon) SETENV:NOPASSWD:
/usr/lib/xymon/client/ext/postfix.sh

In /etc/xymon/clientlaunch.d/xymon/postfix.cfg:
CMD /usr/bin/sudo -E -u postfix -g xymon $XYMONCLIENTHOME/ext/postfix.sh

In /var/lib/xymon/tmp:
chmod g+w -R .

Is that a reasonable permission fix, or should I have done it a
different way?

Separate issue, more annoying than a real problem:  Both xymonton and
the download site for the postfix queue monitor script are using
self-signed certificates.  It is not difficult to obtain zero-cost
publicly-signed certificates that work in all modern browsers, so I
think this should be fixed.

Thanks,
Shawn